<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>grid</title>
  </head>
  <body>
    <div class="cube">
      <div class="side front">1</div>
      <div class="side back">6</div>
      <div class="side right">4</div>
      <div class="side left">3</div>
      <div class="side top">5</div>
      <div class="side bottom">2</div>
    </div>
  </body>
  <style>
    .cube {
        font-size: 4em;
        width: 2em;
        margin: 1.5em auto;
        transform-style: preserve-3d;
        transform: rotateX(-35deg) rotateY(30deg);
    }

    .side {
        position: absolute;
        width: 2em;
        height: 2em;
        background: rgba(255, 99, 71, 0.6);
        border: 1px solid rgba(0, 0, 0, 0.5);
        color: white;
        text-align: center;
        line-height: 2em;
    }

    .front {
        transform: translateZ(1em);
    }

    .bottom {
        transform: rotateX(-90deg) translateZ(1em);
    }

    .top {
        transform: rotateX(90deg) translateZ(1em);
    }

    .left {
        transform: rotateY(-90deg) translateZ(1em);
    }

    .right {
        transform: rotateY(90deg) translateZ(1em);
    }

    .back {
        transform: translateZ(-1em);
    }
</style>

</html>
